Saturday, 17 May 2014

Pent-cil Box

Pent-cil Box

Jerry Loo. For my other puzzle designs, click here and here.

Pelikan. They can be contacted at

Type & Classification
3D Packing.

17cm (Length) x 5cm (Width) x 4cm (Height).

Materials & Construction
A combination of 2 hardwoods; Wenge for the box and Cherry for the pieces. Construction is excellent with great attention to detail. The pieces have bevelling to all their edges and their fit inside the box is just nice, although I would suspect that high humidity environments may cause the puzzle to tighten up.

After my Ball In Cylinder #1 and #2, I decided to try my hand at designing a puzzle to be made in wood. I couldn't really think of any more tricks using a cylinder shape design. Moreover, fabricating a puzzle in metal is also a far more difficult, tedious and expensive process.

All of my wood puzzle designs so far have been packing puzzles, done "by hand", since I do not have the skills nor knowledge of specialised computer software to create high level (or for that matter low level) burrs or interlocking puzzles. My only technical resource is Burr Tools which not only aids but also validates my designs. And not to mention the thrill of watching a puzzle design that works coming to life! For most part, I use an Excel spread sheet (amongst other things, for determining square units and shapes etc) and centimetre cubes to build and test working models.   

Most folks that see this think they belong to my 4 year old son
....they're actually for me to play with!
My first attempt was a rectangular box packing puzzle with a series of irregular odd shapes to fill it. It was fine as an ordinary packing puzzle but a bit "crude" from a design standpoint and totally lacking any finesse. Fellow Singaporean and puzzle designer Goh Pit Khiam gave me some useful tips on puzzle designing; like having a theme (eg using Pentominoes) or ensuring symmetry in the design etc. With his help, I learnt new things along the way and improved. And eventually came up with my first wood puzzle design, the Pento Pack Rectangular. I have designed several other variations thereafter using the same "Pento" theme.

And then there is Ishino-san with his puzzlewillbeplayed site. Very inspiring! Even though my simple designs are terribly amateurish compared to those from the regular big name designers that pop up every week, it does feel nice to see one's design "published" on the site. Not only that but also for the very practical reason to stake copyright ownership.

This particular puzzle is called the "Pent-cil Box"; for several reasons:-

1. Its been designed to look like a traditional wooden pencil box.
2. The pieces comprise the full set of 12 flat Pent-ominoes; each piece being made up of 5 square units.
3. There is only one solution, requiring the packing of all 12 pieces PLUS a real (albeit short) pencil, flush into the box. 

Difficulty Level
Honestly I can't gauge its difficulty! I have not had the opportunity to test this puzzle on anyone else, other than myself and sometimes I forget the sequence too. But given it has 13 pieces (including the pencil), I don't think its a walk in the park and some puzzlers will likely have to resort to the solution (or Burr Tools). how does one specify a pencil in Burr Tools? Ha Ha :-)


  1. Congratulations. I've tried a couple of times to get in touch with Ishino-san to have the designs I've made published, but I've never had a response. I eventually gave up.

  2. Thanks, Neil.

    From what I can see on Ishino's site, almost all the puzzles there are rectilinear interlocking, packing or burr puzzles, although a number have rotations etc...puzzles that his own software can analyse. I think if your puzzle falls outside of these genres, it may not get published.

    From my own experience, he also does not upload every design I send him, I had one that was 37 units long....didn't get published; maybe because of the size.

    I am not sure what criteria he uses or how he selects what to publish on the site.